Playwright MCP Server

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already provide readOnlyHint=true, destructiveHint=false, and openWorldHint=true, indicating a safe, non-destructive operation. The description adds context by specifying it captures an 'accessibility snapshot' and compares it to a screenshot, but it doesn't disclose additional behavioral traits like what data is included, format details, or any limitations. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence that front-loads the core purpose. It avoids unnecessary words, though it could be slightly more informative (e.g., clarifying what an accessibility snapshot includes). Every part of the sentence contributes to understanding the tool's intent.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool has annotations covering safety (readOnly, non-destructive) and one parameter with full schema coverage, the description is adequate but minimal. It lacks details on output (no output schema) and doesn't fully explain the 'accessibility snapshot' concept or how it differs from a screenshot, leaving gaps for an agent to infer usage.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with one parameter 'filename' fully documented in the schema. The description doesn't add any parameter-specific information beyond what the schema provides, such as file format or usage examples. With high schema coverage, the baseline score of 3 is appropriate as the description doesn't compensate but also doesn't detract.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb ('capture') and resource ('accessibility snapshot of the current page'), making the purpose understandable. It distinguishes from the sibling 'browser_take_screenshot' by specifying 'accessibility snapshot' and noting it's 'better than screenshot,' though it doesn't fully explain what an accessibility snapshot entails beyond that comparison.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage by comparing to 'screenshot,' suggesting it's for capturing page information in a more accessible format, but it doesn't explicitly state when to use this tool versus alternatives like 'browser_take_screenshot' or other browser tools. No clear exclusions or prerequisites are provided.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.